The rest of the Presentation API IDL as stubs.

Source/modules/presentation/Presentation.idl

Index: Source/modules/presentation/Presentation.idl
diff --git a/Source/modules/presentation/Presentation.idl b/Source/modules/presentation/Presentation.idl
index 1546a1dbd34d8fcd9b995e269d37a37cae91205f..c28ed2e27aa83ca1b276023e7e25ee29a0d216f6 100644
--- a/Source/modules/presentation/Presentation.idl
+++ b/Source/modules/presentation/Presentation.idl
@@ -2,11 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// http://webscreens.github.io/presentation-api/#presentation-interface
+// http://webscreens.github.io/presentation-api/#navigatorpresentation
 
 [
     GarbageCollected,
     RuntimeEnabled=Presentation
 ] interface Presentation : EventTarget {
+    readonly attribute PresentationSession? session;
+    [CallWith=ScriptState] Promise startSession(DOMString senderId, DOMString? presentationId);

[Peter Beverloo, 2014/10/29 20:51:19]

Fwiw, nullable and optional are not the same thing here. Do you mean to include
the "optional" keyword?

[whywhat, 2014/10/29 22:09:27]

Done.

+    [CallWith=ScriptState] Promise joinSession(DOMString senderId, DOMString? presentationId);
     attribute EventHandler onavailablechange;
 };